Limework at St Cwyfan's Church-in-the-sea

Ned Schärer

The ancient church of St Cwyfan, Llangwyfan before limewashing, with the mountains of Snowdonia
in the background

On a quiet area of the west coast
of Anglesey, between the villages
of Aberffraw and Rhosneigr, a tiny
walled island projects from the rocky shore
out into the Irish Sea. On it, battered by the
elements, stands the ancient church of St
Cwyfan. When the tide is high the church and
its island churchyard are surrounded by the sea,
and even the narrow, boulder-strewn causeway
which connects it to the shore is frequently submerged. It is a dramatic setting, and as
hostile an environment as any faced by soft
lime mortar and limewash in the British Isles.

By the spring of 2005 when the current
programme of conservation work was due to
commence, the exterior fabric of the building
was in a poor state of repair. The walls had
been pointed with a hard cement mortar, and
the windows replaced with polycarbonate
sheet. The programme of works involved
repairs to the external envelope of the building,
including new leaded glazing, and some
internal decoration, although this article will
focus on the exterior treatment of the walls.
To the architect Adam Voelker and
contractors Cadwraeth Schärer Conservation
it was clear from the outset that very little
in this job would be plain sailing. While the
contractors were busy planning how to get
15 tonnes of materials across the causeway
between high tides and up the steep stone steps,
and all the rubble back to the mainland, other
people had different concerns. The specification
included removal of the heavy cement pointing,
re‑pointing with lime and then limewashing.
A small but determined group of local people
was unhappy about the limewash, because no
one could ever remember the church being
white, and they campaigned vigorously against it.
Cadw was involved in the funding of the project,
and the specification had to remain unchanged – there was no room for compromise.

The work was not finally given the go ahead
until July 2006, over 18 months late and well into
the short summer working window available on
such an exposed site. With hindsight this may
well have been for the best; inevitably, problems
arose very quickly with the onset of autumn
conditions. Had the contract been given a clear
run at the height of summer, the problems
may not have become apparent so quickly.

The most exciting part of the project was
always going to be the removal of the old cement
mortar: as this would provide the archaeologists
with a rare opportunity to do a detailed survey
of stonework that had not been properly visible
for hundreds of years. The old pointing was
removed in early August, very carefully, using
only hand tools. This sounds straightforward,
but the truth was that the weather made every
process difficult. The raking out was hard
on the wrists, but the dust blown out of the
joints by the sea breeze resulted in constantly
irritated eyes. Safety glasses protected the
stonemasons from bits flying off, but not from
the swirling dust – swimming goggles worked,
but vanity dictated that the masons only wore
them at high tide when there were no visitors.
When the raking out was finished
the contractors left the site for a
couple of weeks to allow Gwynedd
Archaeological Trust to do its work.

Above left: the arcade begins to re-appear. Above right: the north wall as the hard cement is removed

THE EVIDENCE UNCOVERED

It is unclear why the church is where it is; it is
certainly not the most convenient of locations – a new church was built for the parish in 1872
a little way inland. There are dozens of ancient
churches and religious sites on Anglesey,
and this site, despite the presence of a noisy
race track on the adjacent headland, and the
proximity of two RAF bases, must retain as
much of a spiritual atmosphere as any. Those
of us working on the job, especially when we
camped there because of the tides, and visitors
who came across the causeway, almost always
commented on the very special feel of the place.

Aberffraw, a mile to the south east of
St Cwyfan’s was once a maerdref or manor
house belonging to the kings of Gwynedd,
and the building may have received some kind
of royal patronage. During the 12th century
and again during the 15th century, after the
havoc dealt by the Black Death in the middle
of the 14th century, Gwynedd was relatively
stable and prosperous. These periods coincide
with significant archaeological findings.

There are two types of stone used in the
building: sandstone grit thought to be from the
Bodorgan Paradwys area on the north side of
the Malltraeth estuary, about four miles from
the site; and schist, a metamorphic crystalline
rock which exhibits a layered structure and is
found plentifully on the shoreline at Llangwyfan.
The archaeologists believe that the evidence
points to the earliest stone church on the
site being built in the 12th century using the
sandstone. There is a clearly defined projecting
string course of very weathered moulded
sandstone half way up the wall on either side of
the door, to just beyond the first window. There
is a similar feature in remaining 12th century
masonry at Aberffraw church. It has long been
known that the present door arch, although very
old, had been fitted into a larger and older arch,
and when the old pointing was stripped away it
was possible to see the earlier doorway with its
distinctive semi-circular arched head – which is
possibly 12th century. It was also possible to see
clearly that the lower courses of the west gable,
and the westerly half of the south wall, were
constructed with small neatly cut sandstones;
and it was easier to see the string course. (This
is shown in the archaeologist’s drawings below).

Gwynedd Archaeological Trust's records of the north wall (top) and the south wall (bottom)

During the later part of the 14th century
it is thought that the church was repaired or
extended to its present length using large and
irregular pieces of local schist, while some of the
squared sandstone from the original building
was incorporated into the quoins. By the end
of the 15th century the church had changed
yet again, with the addition of a second aisle
on the north side linked to the original church
by an arcade of three arches. This second aisle
was demolished sometime between 1802 and
1846, presumably after an unsuccessful struggle
against the sea and the elements. The shape of
the three sandstone arcade arches was always
visible from inside the church, but had been
hidden in modern times by the outside mortar.

REPAIR WORK

Once the archaeologists had finished, the
contractors were able to complete the next
stages of the job: minor repairs to the roof
and the re-pointing. The specification for the
pointing was 1 part naturally hydraulic lime
(NHL) of strength class 3.5, to 2–2.5 parts
sharp, well-graded sand (3-4mm grit) from
Cefn Grainog quarry south of Caernarfon.
Shells from the beach were washed to remove
the salt and added to the mix to match the
original mortar. Visual analysis and a quick
dissolution test suggested that the original
mortar was very lime rich and that the sand
looked identical to that found on the beach. We
do not know whether the water in the original
mix was fresh or straight out of the sea.

The decision was taken early on that
the work would be as low-tech as possible,
mixing the mortar by hand using a larry and
shovel in a plasterer’s trough on the island.
The mix was well worked and left to fatten
up for a few hours; it was then knocked up
again into a stiff mortar which would be
easy to work and compress into the joints.

After doing small masonry repairs and
dubbing out a few areas, the mortar was
finished flush to the stonework and then worked
into the edges of the stone with hessian or a stiff
brush when it was slightly soft, to get a good
bond and to weatherproof joints with efficient
run-off for the rain and sea-spray. Once the mortar had firmed up enough, it was beaten
with a churn brush and the aggregate brought
to the surface by scraping back with a trowel
and leaf (a small pointing tool). It was then kept
damp for a week under hessian sheets. The
weather was difficult to deal with especially
when the protecting hessian blew away. The
masons had to work quickly and cover the
mortar immediately from the drying wind and
sun. Fortunately, it was possible to staple-gun
the hessian to the wall plate – without which
the wind would have caused a real problem.

As the intention was to limewash the
walls afterwards, it was decided to experiment
with three different types of hydraulic lime,
St Astier, Castle and Singleton Birch, partly to
test their workability, and perhaps also their
longevity. All three worked well, but the British
lime, Singleton Birch, was the nicest to use in
these conditions because it stayed workable
for longer and made a slightly fattier mortar.

The re-pointing had gone to plan and
even transporting the materials to and from
the beach across the causeway did not present
too much of a problem – everything from
a horse and cart to a helicopter had been
considered, but in the end a dumper truck
solved the problem. By now it was mid-September and the weather was worsening.
With some apprehension an attempt was
made to limewash the north, east and south
walls, only to find that with a day or so of
heavy rain, most of the limewash, particularly
on the exposed south wall, was washing off.

It was clear that a re-think was necessary
and after talking to the vicar Canon Madalaine
Brady and Adam Voelcker the architect, it
was decided to do some trials over the winter
to see what would work best. At this stage
the two most sheltered sides, the north wall
and the east gable wall were reasonably well
covered with limewash. The long south wall
was very patchy; at that stage no attempt to
limewash the west gable wall had been made.

At that time the problems with the
limewash were very disheartening, but a year
later I can say that the learning experience
and experimental tests proved to be of great
interest and will, I hope, help others in similar circumstances. The problem was twofold – the
difficulty of limewashing large expanses of wall
with full exposure to the ever-changing weather,
and the non-porous schist. The wind proved
to be the hardest of the elements to deal with:
windbreaks were tried, but they blew down as
the wind changed direction so often; hessian
sheets stayed in place, but they flapped against
the fresh limewash and rubbed it off. As for the
stone, the schist, a non-porous metamorphic
rock simply would not take the limewash: it was
as if it had been sprayed with a water-repellent.

To find the best constituents, trials were
carried out on the south wall over the winter.
These included a shelter coat mixed in an
ordinary fat (non-hydraulic) lime and one
with a binder of casein, a shelter coat mixed
in a feebly hydraulic lime, and a straight
hydraulic limewash. Each sample patch had
five coats. After six months of winter and
spring weather, the shelter coat mixed in a
feebly hydraulic lime was the most successful,
and all the trials had worked better than
the straight non-hydraulic limewash.

In the summer of 2007 the team set to
and re-limewashed the whole church. The
south wall was brushed back with a stiff brush
and all the weakly bonded previous limewash
removed. Five coats of the shelter-coat were
applied, consisting of one part Singleton Birch
NHL2 to two parts fine sand. One stroke of luck
was that the shelter coat dried a very similar
colour to the Ynys Mon pigment – a naturally
occurring material from Parys Mountain near
Amlwch which had been in the specification.

The benefit of using a hydraulic lime was
that it went off more quickly and therefore could
cope with the weather sooner. With the slight
set of the hydraulic lime the hessian protection
did not cause as much abrasive damage, and
we were able to damp down the surface sooner
on dry and windy days. A week was allowed
between each coat so the limewash could fully
carbonate. After each application the craftsman
went over the surface with a dry stock brush
to remove any loose material, then wetted
down the wall and repeated the process.

The shelter coat was almost a slurry in
consistency and had to be applied with the
brush from a plastic dust pan and brush set,
because the sand clogged normal brushes.
The speed with which it could be applied
in this way meant that there was extra time
to look after the fresh walls and keep them
damped down. Another added attraction of this
method is that it is closer to the old-fashioned
local method of using a long-handled broom
to apply limewash. I shall try it again in the
future, or possibly even flick the shelter coat
on, as in the manner of harling or rough cast.

Top: the south and west wall with its bright new limewash seen from the churchyard. Above left: the south side in
January 2007 showing the Norman arch over the entrance. Above right: the south and east walls seen from the shore

Work on the exterior eventually finished
in the summer of 2007, and at the time
of publishing this article the church looks
complete, with the soft whiteness of the
limewash constantly changing, lightening and darkening as first one wall and then the next is
lit by the sun, or wetted by rain or sea spray.

There have been times over the past year
or so when I wondered if we were taking the
best course of action for the building in the
long term. Of course removing the cement
was essential, but I wondered if it might have
been better to have either left the masonry
and new pointing bare without a shelter coat,
or to have gone further than we did and fully
harl the building. In the end I think we got it
right: we have protected the building from
the elements and the sea spray but at the
same time the archaeology can still be read.

However, for all this work to have been
worthwhile, the shelter coat, particularly
on the two most exposed walls must be
re-applied regularly. Over time, if it is done
properly, the layers will build up like a shell
and it should be possible for the intervals
between applications to become longer. The
building would be in an even better state
if funding could be found before too long to remove the cement patches and areas of
emulsion paint from the inside walls, and
replace them with lime mortar and limewash.

This
article is reproduced from Historic Churches, 2007

Author

NED SCHÄRER of Cadwraeth Schärer
Conservation, wishes to acknowledge the
help of DAVID LONGLEY of Gwynedd
Archaeological Trust in compiling this article.